Optically active compounds obtained by asymmetric conjugate addition reaction to electron-deficient olefin such as nitroolefin compound, α,β-unsaturated carbonyl compound and the like are useful as intermediates for synthesizing amines, amino acids, medicaments, agricultural chemicals, food additives and the like (e.g., Journal of the American Chemical Society, vol. 124, No. 44, p. 13097-13105 (2002)), and various production methods have been reported so far.
In the reports, as a non-metal asymmetric catalyst for a conjugate addition reaction, it has been reported that asymmetric urea compound represented by the following formula:
can be used as a non-metal asymmetric catalyst for a stereoselective conjugate addition reaction (patent document 1).
In addition, there are a number of biologically active compounds in the nature, such as lactacystin, myriocin, kaitocephalin, oxazolomycin and the like, which are expected to be applicable to pharmaceutical products. All of these compounds have an α-amino acid structure containing an optically active quaternary carbon, and are considered to be deeply involved in the biological activity. Construction of an asymmetric tetra-substituted carbon containing a nitrogen atom is an important object in the organic synthesis chemistry, and various synthesis methods have been reported heretofore.
Among them, a report has documented that the above-mentioned asymmetric urea compound can be used as a non-metal asymmetric catalyst for a stereoselective carbon-nitrogen bond formation reaction (patent document 2).